This invention relates to a freeze seal and freeze clamp for cables, wires, optical fibers and other elements requiring a seal or a clamp.
The present invention can be used, for example, for testing cables or hardware components having a cable connected thereto. Undersea cable and undersea hardware components for example require testing during development and as part of quality assurance. According to one procedure, in order to test such cable or hardware component, the cable or hardware component is disposed in a pressure vessel and the pressure vessel pressurized to the desired test pressure. However, it is necessary that the cable extend externally of the pressure vessel because only a small section or mid-span portion of an elongated cable may be tested or because the hardware component being tested has a cable connected thereto which extends externally of the pressure vessel. Since the cable is required to penetrate the pressure vessel, it is necessary to provide a seal between the cable and the pressure vessel in order that the pressure vessel can be pressurized.
Heretofore, such seal was a gland seal which was specifically modified to accommodate the requirements of the particular cable which penetrated the pressure vessel. For example, the seal would have to be modified depending on the physical characteristics of the particular cable being tested such as its diameter, cross sectional geometry, surface characteristics, the material of the cable and whether there was one or more cables to be sealed. Such modifications would often result in requiring a redesign of the seal for different cables in order to adapt the seal to the particular cable or cables to be tested.
It is desirable that a seal used for testing of such cables and hardware components include the following characteristics:
(a) the seal should be a universal pressure seal that conforms directly to the outer layer of the cable regardless of cable size, construction, or surface condition; PA1 (b) the seal should have a zero leak rate; PA1 (c) the seal should provide a force capable of restraining the cable from moving through the seal at the maximum chamber pressure; PA1 (d) the seal should be easy to install and remove; PA1 (e) the seal should not damage or degrade the performance of the cable; and PA1 (f) the seal should operate on cables at the free ends or at mid-span, that is, the pressure vessel and cable seal can be modified to a split design that is capable of capturing the cable anywhere along the length of the cable, for example, for local pressure testing of a repeater or splice housing in the center or mid-span of a long cable on a factory floor.